1. Field of the Invention
The present invention relates to a fuel supply system for a motorcycle. More particularly to a fuel supply system which has a space-saving design in regard to the installation space thereof and in which a fuel filter device is firmly supported.
2. Description of Background Art
A fuel supply system for a motorcycle wherein a fuel filter device is disposed on the downstream side of a fuel pump unit is shown in Japanese Patent Laid-open No. 2008-248753 (FIGS. 1 to 3, 5 and 6). The fuel supply system shown in Japanese Patent Laid-open No. 2005-096504 (FIGS. 1 and 2) has a configuration in which while the fuel pump unit is provided inside a fuel tank, the fuel filter device is disposed on the rear side of a throttle body and on the upper side of a crankcase, and is mounted through a bracket to a center frame extending vertically on the rear side of a power unit.
On the other hand, a system in which, due to a restriction imposed by a fuel tank or the like, a fuel pump unit is disposed on the upper side of an output shaft in a crankcase of a power unit and on the front side of a rear cushion is shown in Japanese Patent Laid-open No. 2005-096504.
In a fuel supply system for a motorcycle having a fuel filter device provided on the downstream side of a fuel pump unit as shown in Japanese Patent Laid-open No. 2008-248753, a further space saving in regard of layout space while achieving a further firm supporting of the fuel filter device has been requested.
More particularly, in the case of a motorcycle using a gasoline-ethanol mix fuel as described in Japanese Patent Laid-open No. 2008-248753, it is highly necessary to provide a fuel filter device on the downstream side of the fuel pump unit for the purpose of removing the dust present in ethanol, and there has been a demand for firm supporting of the fuel filter device outside a fuel tank.
In that case, also, there has been a demand for a fuel supply system having a space-saving configuration in which a fuel pump unit can be disposed outside the fuel tank, like in Japanese Patent Laid-open No. 2005-096504.